NCT04155619.

Study name	Using early time restricted feeding and timed light therapy to improve glycemic control in adults with type 2 diabetes
Methods	Randomised controlled trial
Participants	Ages Eligible for Study: 30 years to 80 years (adult, older adult) Sexes Eligible for Study: all Accepts Healthy volunteers: no Inclusion Criteria Aged 30‐80 years old HbA1c between 7.0 % to 10.0% On a stable dose of metformin, sulphonylureas, DPP‐IV inhibitors, and/or GLP‐1 receptor agonists for at least 6 months, or taking no diabetes medications Stable values of HbA1c for the past 6 months (within 0.7%) Wake up at a regular time between 5 am to 9 am
Interventions	Active Comparator: no change in eating or light exposure habits Behavioural: no change in meal timing Participants will eat within an ≥11‐hour daily period (no change in meal timing habits). Behavioural: no change in light exposure Participants will not change their light exposure habits. Experimental: early Time‐Restricted Feeding Behavioural: no change in light exposure Participants will not change their light exposure habits. Behavioural: early Time‐Restricted Feeding Participants will eat within an 8‐hour daily period early in the day, starting within 2 hours of waking up. Other name: eTRF, early TRF Experimental: Timed Light TherapyBehavioural: No change in meal timing Participants will eat within an ≥11‐hour daily period (no change in meal timing habits). Behavioural: Timed Light Therapy Participants will use bright light therapy for 60 minutes between 6 am to 3 pm, blue light‐blocking glasses for one hour before bedtime, and blackout curtains at night. Other name: Bright Light Therapy Experimental: Early Time‐Restricted Feeding and Timed Light TherapyBehavioural: Early Time‐Restricted Feeding Participants will eat within an 8‐hour daily period early in the day, starting within 2 hours of waking up. Other name: eTRF, early TRF Behavioural: Timed Light Therapy Participants will use bright light therapy for 60 minutes between 6 am to 3 pm, blue light‐blocking glasses for one hour before bedtime, and blackout curtains at night. Other name: Bright Light Therapy
Outcomes	Primary Outcome Measures : 24‐hour glucose levels [ Time Frame: 16 weeks ] Time‐weighted mean, fasting, peak, standard deviation, and excursion (maximum ‐ minimum) values (mg/dl) 24‐hour insulin levels [ Time Frame: 16 weeks ] Time‐weighted mean, fasting, peak, standard deviation, and excursion values (mU/L) 24‐hour C‐peptide levels [ Time Frame: 16 weeks ] Time‐weighted mean, fasting, peak, standard deviation, and excursion values (pmol/L). This is also a proxy for total 24‐hour insulin secretion. Hemoglobin A1C [ Time Frame: 16 weeks ] Insulin sensitivity [ Time Frame: 16 weeks ] Insulin sensitivity (dl/kg/min/μU/mL) during three identical meal tolerance tests, as measured by the Oral Minimal Model. The individual, mean, and excursion values, and time of the peak value will also be calculated. Beta‐cell responsivity index (a measure of beta‐cell function) [ Time Frame: 16 weeks ] Beta‐cell responsivity during three identical meal tolerance tests, as measured by the Oral Minimal Model. The individual, mean, and excursion values, and time of the peak value will also be calculated. Insulin secretion [ Time Frame: 16 weeks ] Insulin secretion (mU) across three identical meal tolerance tests, as measured by the Oral Minimal Model. The individual, mean, and excursion values, and time of the peak value will also be calculated. Secondary Outcome Measures: Melatonin Amplitude [ Time Frame: 16 weeks ] Peak value (pg/mL) Cortisol Amplitude [ Time Frame: 16 weeks ] Amplitude (μg/dL) Melatonin Phase [ Time Frame: 16 weeks ] Clock time of dim light melatonin onset (DLMO) Cortisol Phase [ Time Frame: 16 weeks ] Clock time of cortisol phase Glycemic ("Peripheral") Rhythm Amplitude [ Time Frame: 16 weeks ] Amplitude or diurnal variation in glucose levels (mg/dl) during a constant glucose infusion procedure Glycemic ("Peripheral") Rhythm Phase [ Time Frame: 16 weeks ] Time of day that glucose levels experience a nadir during a constant glucose infusion procedure
Starting date	March 2020
Contact information	cpeterso@uab.edu
Notes	NCT04155619